This invention relates to actuating downhole tools, specifically tools for oil, gas, geothermal, and horizontal drilling. Downhole tool actuation is sometimes accomplished by dropping a ball down a bore of a drill string which may lead to the breaking of a shear pin, which, upon breaking, frees a valve to open, thus actuating a tool such as a reamer or stabilizer. Once the pin is broken however, the drill string must generally be removed from the hole and the pin replaced before the tool can be actuated again.
U.S. Pat. No. 7,308,937 to Radford, et al. which is herein incorporated by reference for all that it contains, discloses that a flow restriction element may be disposed within a drill string to actuate the expansion of an expandable reamer. For instance, a ball may be disposed within the drilling fluid, traveling therein, ultimately seating within an actuation sleeve disposed at a first position. Pressure from the drilling fluid may subsequently build to force the ball and actuation sleeve, optionally held in place by way of a shear pin or other friable member, into a second position, thereby actuating the expansion of the expandable reamer. Such a configuration may require that once the movable blades are expanded by the ball, in order to contract the movable blades, the flow is diverted around the seated ball to allow a maximum fluid flow rate through the tool. Thus, the expandable reamer may be configured as a “one shot” tool, which may be reset after actuation.